The fluorine atom, by virtue of its electronegativity, size, and bond strength with carbon, can be used to create compounds with remarkable properties. Small molecules containing fluorine have many positive impacts on everyday life of which blood substitutes, pharmaceuticals, and surface modifiers are only a few examples. Fluoropolymers, too, while traditionally associated with extreme hi- performance applications have found their way into our homes, our clothing, and even our language. A recent American president was often likened to the tribology of PTFE. Since the serendipitous discovery of Teflon at the Dupont Jackson Laboratory in 1938, fluoropolymers have grown steadily in technological and marketplace importance. New synthetic fluorine chemistry, new processes, and new apprec- tion of the mechanisms by which fluorine imparts exceptional properties all contribute to accelerating growth in fluoropolymers. There are many stories of harrowing close calls in the fluorine chemistry lab, especially from the early years, and synthetic challenges at times remain daunting. But, fortunately, modern techniques and facilities have enabled significant strides toward taming both the hazards and synthetic uncertainties. In contrast to past environmental problems associated with fluorocarbon refrigerants, the exceptional properties of fluorine in polymers have great environmental value. Some fluoropolymers are enabling green technologies such as hydrogen fuel cells for automobiles and oxygen-selective membranes for cleaner diesel combustion.

In the future, our energy systems will need to be renewable and sustainable, efficient and cost-effective, convenient and safe. Hydrogen has been proposed as the perfect fuel for this future energy system. The availability of a reliable and cost-effective supply, safe and efficient storage, and convenient end use of hydrogen will be essential for a transition to a Hydrogen Economy. Research is being conducted throughout the world for the development of safe, cost-effective hydrogen production, storage, and end-use technologies that support and foster this transition. This book is a collection of important research and analysis papers on hydrogen production, storage, and end-use technologies that were presented at the American Chemical Society National Meeting in New Orleans, Louisiana, USA, in August 1999.

This monograph describes and discusses the properties of heterogeneous materials, including conductivity, elastic moduli, and dielectrical constant. The book outlines typical experimental methods, and compares the experimental data and the theoretical predictions. This multidisciplinary book will appeal to applied physicists, materials scientists, chemical and mechanical engineers, chemists, and applied mathematicians.

Proceedings of the International School of Quantum Electronics 27th course on Bose Einstein Condensates and Atom Lasers, October 19-24, 1999, Erice, Italy. Since the experimental demonstration of Bose Einstein Condensation in dilute atomic gases there has been an explosion of interest in the properties of this novel macroscopic quantum system. The book covers the methods used to produce these new samples of coherent atoms, their manipulation and the study of their properties. Emphasis is given to the anticipated development of new types of sources, which more and more resemble traditional types of lasers. Because of recent new applications and increasing demand for lasers, sensors and associated instrumentation, the chapters also cover current developments in the basic techniques, materials and applications in the field of the generation of coherent atoms.

Stereology is the science that relates three-dimensional structure to the two-dimensional images that can be measured. The most common field of application is in microscopy, both of man-made materials (metals, ceramics, composites, etc.) and of biological tissue samples. This book covers the applications and terminology of both fields. Recent emphasis in stereology is concerned with sampling strategies to avoid bias due to directionality and non-uniformity, and these methods are fully covered. So are the classic techniques that measure size distributions, surface curvature, etc., which are widely useful but not discussed in other recent texts. Finally, most stereology is taught as manual procedures using counting and grids, but this text also covers the use of modern desktop computers for image analysis and processing to obtain and interpret the stereological data.

The field of nonlinear optics, which has undergone a very rapid development since the discovery of lasers in the early sixties, continues to be an active and rapidly developing - search area. The interest is mainly due to the potential applications of nonlinear optics: - rectly in telecommunications for high rate data transmission, image processing and recognition or indirectly from the possibility of obtaining large wavelength range tuneable lasers for applications in industry, medicine, biology, data storage and retrieval, etc. New phenomena and materials continue to appear regularly, renewing the field. This has proven to be especially true over the last five years. New materials such as organics have been developed with very large second- and third-order nonlinear optical responses. Imp- tant developments in the areas of photorefractivity, all optical phenomena, frequency conv- sion and electro-optics have been observed. In parallel, a number of new phenomena have been reported, some of them challenging the previously held concepts. For example, solitons based on second-order nonlinearities have been observed in photorefractive materials and frequency doubling crystals, destroying the perception that third order nonlinearities are - quired for their generation and propagation. New ways of creating and manipulating nonl- ear optical materials have been developed. An example is the creation of highly nonlinear (second-order active) polymers by static electric field, photo-assisted or all-optical poling. Nonlinear optics involves, by definition, the product of electromagnetic fields. As a con- quence, it leads to the beam control.

The need for alternate energy sources has led to the develop ment of prototype fusion and MHD reactors. Both possible energy systems in current designs usually require the use of magnetic fields for plasma confinement and concentration. For the creation and maintenance of large 5 to 15 tesla magnetic fields, supercon ducting magnets appear more economical. But the high magnetic fields create large forces, and the complexities of the conceptual reactors create severe space restrictions. The combination of re quirements, plus the desire to keep construction costs at a mini mum, has created a need for stronger structural alloys for service at liquid helium temperature (4 K). The complexity of the required structures requires that these alloys be weldable. Furthermore, since the plasma is influenced by magnetic fields and since magnet ic forces from the use of ferromagnetic materials in many configur ations may be additive, the best structural alloy for most applica tions should be nonmagnetic. These requirements have led to consideration of higher strength austenitic steels. Strength increases at low temperatures are achieved by the addition of nitrogen. The stability of the austenitic structure is retained by adding manganese instead of nickel, which is more expensive. Research to develop these higher strength austenitic steels is in process, primarily in Japan and the United States."

For several years, core level spectroscopies and other, c\osely related, electron spectroscopies have provided very useful information about the atomic composition, the geometric structure, and the electronic structure of condensed matter. Recently, these spectroscopies have also been used for the study of magnetic properties; such studies have a great potential to extend our knowledge and understanding of magnetic systems. This volume collects the lectures presented at the NATO Advanced Study Institute on "Core Level Spectroscopies for Magnetic Phenomena: Theory and Experiment" held at the Ettore Majorana Centre, Erice, Sicily, on 15 to 26 May 1994. The topics considered at the ASI covered a wide range of subjects involving the use of core-level and related spectroscopies to study magnetic phenomena. There are a large and growing number of applications of these spectroscopies to the study of magnetic materials; an important objective of the ASI was to stimulate further growth. The topics covered at the ASI can be placed into three general groups: 1) fundamental principles of core level spectroscopies; 2) basic aspects of magnetic phenomena; and, 3) the combination of the two previous topics embodied in applications of the spectroscopies to magnetism. In all three groups, theoretical interpretations as weH as experimental measurements were presented, often both of these aspects were covered in a single lecture or series oflectures. The theoretical treatments ofthe spectroscopies as weH as of the magnetic phenomena help to establish a framework for understanding many of the experimental measurements on magnetic materials.

Stochastic geometry, based on current developments in geometry, probability and measure theory, makes possible modeling of two- and three-dimensional random objects with interactions as they appear in the microstructure of materials, biological tissues, macroscopically in soil, geological sediments etc. In combination with spatial statistics it is used for the solution of practical problems such as the description of spatial arrangements and the estimation of object characteristics. A related field is stereology, which makes possible inference on the structures, based on lower-dimensional observations. Unfolding problems for particle systems and extremes of particle characteristics are studied. The reader can learn about current developments in stochastic geometry with mathematical rigor on one hand and find applications to real microstructure analysis in natural and material sciences on the other hand.

During the Koln meeting (August 28-31, 1984), Irdia was chosen as the venue for the next International Conference on Valence Fluctuations. lhis was in recognition ard appreciation of the work done, both experimental ard theoretical, by the Irdian scientists in this area during the last decade. We decided to hold this Conference in the month of January, 1987 at Bangalore. lhe subject of Valence Fluctuations has kept itself alive ard active as it has provided many shocks ard suprises particularly among the Ce- ard U-based intermetallies. lhe richness of many interesting physical phenomena occurring in mixed valent materials, the flexibility of modifying their physical properties (by alloying, for example) ard the possibility of synthesizing a wide variety of new such materials seem to be the key factors in this regard. Barely six months before this Conference, an International Conference on Anomalous Rare Earths and Actinides (ICAREA) had been held at Grenoble (July, 1986) which also focussed on mixed valence ard heavy fermion phenomena. In spite of this, the response to this' Conference was very enthusiastic and encouraging. Many interesting ard important results were presented at this Conference which have been included in this volume.

The liquid crystalline state may be identified as a distinct and unique state of matter which is characterised by properties which resembles those of both solids and liquids. It was first recognised in the middle of the last century through the study of nerve myelin and derivatives of cholesterol. The research in the area really gathered momentum, however, when as a result of the pioneering work of Gray in the early 1970's organic compounds showing liquid crystalline properties were shown to be suitable to form the basis of display devices in the electronic products. The study of liquid crystals is truly multidisciplinary and has attached the attention of physicists, biologists, chemists, mathematicians and electronics engineers. It is therefore impossible to cover all these aspects fully in two small volumes and therefore it was decided in view of the overall title of the series to concentrate on the structural and bonding aspects of the subject. The Chapters presented in these two volumes have been organised to cover the following fundamental aspects of the subject. The calculation of the structures of liquid crystals, an account of their dynamical properties and a discussion of computer simulations of liquid crystalline phases formed by Gay Berne mesogens. The relationships between molecular conformation and packing are analysed in some detail. The crystal structures of liquid crystal mesogens and the importance of their X ray scattering properties for characterisational purposes are discussed.

The subject of mechanical behavior has been in the front line of basic studies in engineering curricula for many years. This textbook was written for engineering students with the aim of presenting, in a relatively simple manner, the basic concepts of mechanical behavior in solid materials. A second aim of the book is to guide students in their laboratory experiments by helping them to understand their observations in parallel with the lectures of their various courses; therefore the first chapter of the book is devoted to mechanical testing. Another aim of the book is to provide practicing engineers with basic help to bridge the gap of time that has passed from their graduation up to their actual involvement in engineering work. The book also serves as the basis for more advanced studies and seminars when pursuing courses on a graduate level. The content of this textbook and the topics discussed correspond to courses that are usually taught in universities and colleges all over the world, but with a different and more modern approach. It is however unique by the inclusion of an extensive chapter on mechanical behavior in the micron and submicron/nanometer range. Mechanical deformation phenomena are explained and often related to the presence of dislocations in structures. Many practical illustrations are provided representing various observations encountered in actual structures of particularly technical significance. A comprehensive list of references at the end of each chapter is included to provide a broad basis for further studying the subject.

This series of books, which is published at the rate of about one per year, addresses fundamental problems in materials science. The contents cover a broad range of topics from small clusters of atoms to engineering materials and involve chemistry, physics, materials science, and engineering, with length scales ranging from Angstroms up to millimeters. The emphasis is on basic science rather than on applications. Each book focuses on a single area of current interest and brings together leading experts to give an up-to-date discussion of their work and the work of others. Each article contains enough references that the interested reader can access the relevant literature. Thanks are given to the Center for Fundamental Materials Research at Michigan State University for supporting this series. M. F. Thorpe, Series Editor E-mail: thorpe@pa. msu. edu East Lansing, Michigan V PREFACE It is hard to believe that not quite ten years ago, namely in 1991, nanotubes of carbon were discovered by Sumio Iijima in deposits on the electrodes of the same carbon arc apparatus that was used to produce fullerenes such as the "buckyball." Nanotubes of carbon or other materials, consisting ofhollow cylinders that are only a few nanometers in diameter, yet up to millimeters long, are amazing structures that self-assemble under extreme conditions. Their quasi-one-dimensional character and virtual absence of atomic defects give rise to a plethora of unusual phenomena."

Making Flory-Huggins Practical: Thermodynamics of Polymer-Containing Mixtures, by B. A. Wolf * Aqueous Solutions of Polyelectrolytes: Vapor-Liquid Equilibrium and Some Related Properties, by G. Maurer, S. Lammertz, and L. Ninni Schafer * Gas-Polymer Interactions: Key Thermodynamic Data and Thermophysical Properties, by J.-P. E. Grolier, and S. A.E. Boyer * Interfacial Tension in Binary Polymer Blends and the Effects of Copolymers as Emulsifying Agents, by S. H. Anastasiadis * Theory of Random Copolymer Fractionation in Columns, by Sabine Enders * Computer Simulations and Coarse-Grained Molecular Models Predicting the Equation of State of Polymer Solutions, by K. Binder, B. Mognetti, W. Paul, P. Virnau, and L. Yelash * Modeling of Polymer Phase Equilibria Using Equations of State, by G. Sadowski

The 39th Annual Denver X-Ray Conference on Applications of X-Ray Analysis was held July 30 -August 3, 1990, at the Sheraton Steamboat Resort and Conference Center, Steamboat Springs, Colorado. The "Denver Conference" is recognized to be a major event in the x-ray analysis field, bringing together scientists and engineers from around the world to discuss the state of the art in x-ray applications as well as indications for future develop ments. In recent years there has been a steady expansion of applications of x-ray analysis to characterize surfaces and thin films. To introduce the audience to one of the exciting and important new developments in x-ray fluorescence, the topic for the Plenary Session of the 1990 Conference was: "Surface and Near-Surface X-Ray Spectroscopy. " The Conference had the privilege of inviting five leading world experts in the field of x-ray spectroscopy to deliver lectures at the Plenary Session. The first two lectures were on total-reflection x-ray fluorescence spectrometry. Professor P. Wobrauschek of Austria reviewed "Recent Developments and Results in Total-Reflection X-Ray Fluorescence. " Trends and applications of the technique were also discussed. Dr. T. Arai of Japan reported on "Surface and Near-Surface Analysis of Silicon Wafers by Total Reflection X-Ray Fluorescence. " He emphasized the importance of using proper x-ray optics to achieve high signal-to-noise ratios. A mathematical model relating the x-ray intensity to the depth of x-ray penetration was also described.

A recent major development in high technology, and one which bears considerable industrial potential, is the advent of low-dimensional semiconductor quantum structures. The research and development activity in this field is moving fast and it is thus important to afford scientists and engineers the opportunity to get updated by the best experts in the field. The present book draws together the latest developments in the fabrication technology of quantum structures, as well as a competent and extensive review of their fundamental properties and some remarkable applications. The book is based on a set of lectures that introduce different aspects of the basic knowledge available, it has a tutorial content and could be used as a textbook. Each aspect is reviewed, from elementary concepts up to the latest developments. Audience: Undergraduates and graduates in electrical engineering and physics schools. Also for active scientists and engineers, updating their knowledge and understanding of the frontiers of the technology.

This volume of Modern Aspects contains seven chapters. The major topics covered in the first six chapters of this volume include fundamentals of solid state electrochemistry; kinetics of electrochemical hydrogen entry into metals and alloys; oxidation of organics; fuel cells; electrode kinetics of trace-anion catalysis; nano structural analysis. The last chapter is a corrected version of chapter four from Volume 35. Faisal M. AI-faqeer and Howard W. Pickering begin the first chapter by going back to 1864 and Cailletet who found that some hydrogen evolved and was absorbed by iron when it was immersed in dilute sulfuric acid. The absorption of hydrogen into metals and alloys can lead to catastrophic failures of structures. They discuss the kinetics of electrochemical hydrogen entry into metals and alloys. In chapter three, Clyde L. Briant reviews the electrochemistry, corrosion and hydrogen embrittlement of unalloyed titanium. He begins by reviewing the basic electrochemistry and general corrosion of titanium. He also discusses pitting and galvanostatic corrosion followed by a review of hydrogen embrittlement emphasizing the formation of hydrides and the effect of these on titanium's mechanical properties. Christos Comninellis and Gy6rgy F6ti discuss the oxidative electrochemical processes of organics in chapter three. They begin by defining direct and indirect electrochemical oxidation of organics. They introduce a model that allows them to distinguish between active (strong) and non-active (weak) anodes. Different classes of organic compounds are used for kinetic models of organic oxidation at active and non-active type anodes.

Bringing Scanning Probe Microscopy Up to Speed introduces the principles of scanning probe systems with particular emphasis on techniques for increasing speed. The authors include useful information on the characteristics and limitations of current state-of-the-art machines as well as the properties of the systems that will follow in the future. The basic approach is two-fold. First, fast scanning systems for single probes are treated and, second, systems with multiple probes operating in parallel are presented. The key components of the SPM are the mechanical microcantilever with integrated tip and the systems used to measure its deflection. In essence, the entire apparatus is devoted to moving the tip over a surface with a well-controlled force. The mechanical response of the actuator that governs the force is of the utmost importance since it determines the scanning speed. The mechanical response relates directly to the size of the actuator; smaller is faster. Traditional scanning probe microscopes rely on piezoelectric tubes of centimeter size to move the probe. In future scanning probe systems, the large actuators will be replaced with cantilevers where the actuators are integrated on the beam. These will be combined in arrays of multiple cantilevers with MEMS as the key technology for the fabrication process.

Crystalline or, more properly, semi-crystalline polymers continue to present major challenges and opportunities to scientists and technologists alike. On the one hand, scientific understanding of their structure and properties still lags behind that of other economically important, but less complicated materials. On the other hand, there remains very considerable potential for improving properties in systems designed for specific pur poses. Ways are only just being found of transferring inherent molecular properties (such as high modulus) to the macromolecular solid. Beyond these are many possibilities of manipulating the organization of chemical and physical textures towards desired ends. The chapters in this volume are reports, by wen-known and active researchers, on some of the important recent developments ofthese themes. Grubb begins with the fundamental and central problem of determining polymeric microstructure. Polymers sutTer by comparison with other materials in that it has not generany been possible to exploit the high resolution of the electron microscope to determine their microstructure in adequate detail. However, recently, ways have been found of studying representative lamellar textures in melt-crystallized polymers. When fully exploited these must add greatly to our detailed knowledge and provide a firmer fundamental base for future developments. Radiation damage bears the primary responsibility for restricting electron microscopy. In his chapter, Kener recounts how appreciation of this fact led him into a fascinating study of ever deeper aspects of radiation damage in polyethylene over two decades, often controversiany but invariably clarifying the basic understanding of an area now of increasing commercial importance."